Highway retroreflecting marker

ABSTRACT

A highway retroreflecting marker comprises a housing including a base having a relatively rigid side wall, and a resiliently depressible cap projecting upwardly from the base. The cap is substantially sealingly engaged with the side wall of the base. At least the cap of the housing is formed from a relatively wearresistant synthetic resin. The cap has a prism which is transparent to enable light rays to pass therethrough and which redirects the light rays striking the prism at an angle different from the angle at which the light rays strike the prism. A retroreflecting means is supported in the housing to enable the light rays redirected from the prism to be received thereby and to enable the light rays received thereby to be retroreflected therefrom back to the prism. The housing is adapted to be positioned adjacent a roadway so that the light rays from an approaching vehicle will strike the prism, be redirected therefrom to the retroreflecting means, then be retroreflected to the prism, and thereafter be directed from the prism back towards the approaching vehicle.

O a United States Patent 1191 1111 B 3,924,958

Rowland Dec. 9, 1975 HIGHWAY RETROREFLECTING MARKER 3,216,335 11/1965Stolarczyk 404/11 [751 Inventor: William Rowland, Millbwok 3325323311323 335321141111: 311135.921)? 52 Lane, Southington, Conn- 064893,377,930 4/1968 Kone 404/11 [73] Assignee: Rowland DevelopmentCorporation,

. Kensington, C Primary ExaminerNile C. Byers, Jr.

22 Pl d: M 7 1973 I 1 ay 57 ABSTRACT [211 Appl 358l74 A highwayretroreflecting marker comprises a housing [44] Published under theTrial Voluntar P t t including a base having a relatively rigid sidewall, and Program on January 28, 1975 as document a resilientlydepressible cap projecting upwardly from B 358,174. the base. The cap issubstantially sealingly engaged Related us. Application Data, :ith theside wall of the base. At least the cap of the ousmg is formed from arelatively wear-resistant syn- [63] gg of 317,263 thetic resin. The caphas a prism which is transparent abandoned to enable light rays to passtherethrough and which redirects the light rays striking the prism at anangle difgg Cell. .hhiFmlii/lg fereht from the angle at which the hghtrays strike the [58] .ld l 12 /0 prism. A retroreflecting means issupported in the 1 2 2? 6 6 housing to enable the light rays redirectedfrom the prism to be received thereby and to enable the light raysreceived thereby to be retroreflected therefrom [56] References cuedback to the prism. The housing is adapted to be posi- UNITED STATESPATENTS tioned adjacent a roadway so that the light rays from 1,797,4983/1931 an approaching vehicle will strike the prism, be redi- 1,902,4403/1933 rected therefrom to the retroreflecting means, then be 311322retroreflected to the prism, and thereafter be directed 2:627:784 2/1953from the prism back towards the approachmg vehlcle. 2,991,698 7/1961Leubaz 404/16 17 Claims, 14 Drawing Figures US. Patent Dec. 9, .1975Sheet 1 of 3 3,924,958

US. Patent Dec. 9, 1975 Sheet 2 of3 3,924,958

US. Patent Dec. 9, 1975 Sheet3of3 3,924,958

HIGHWAY RETROREFLECTING MARKER This application is acontinuation-in-part of my copending patent application, Ser. No.317,263, filed Dec. 21, 1972, and now abandoned.

BACKGROUND OF THE INVENTION It is known in the prior art to employreflecting markers as a means to delineate the lanes including theshoulders of a highway. Particularly in Europe and in warm climates thistype of highway marker is frequently used to glide motorists at nightbecause such markers show up brighter and last longer than conventionalglass filled painted highway stripes.

Each of these markers commonly consists of a strong metal housing whichhouses a glass or plastic prism type reflector. The marker is generallyeither set in a bored hole in the pavement or else is glued to the roadsurface by means, for example, of an "epoxy cement, in such a mannerthat the reflector portion of the marker projects above the road surfacea sufficient distance to provide a visible reflecting surface. Adisadvantage, however, of such markers is that occasionally a markerwill work loose and will be hurled by a passing vehicle into the path ofanother vehicle.

Some use has been made of the aforementioned type of marker in snowclimates. However, when so employed, the markers have exhibited atendency to be easily dislodged by passing snow plows. Various attemptshave been made heretodate to eliminate this problem as well as theproblem mentioned in the preceding paragraph. In general, these efforthave been directed primarily at changing the-configuration of the markerin order to provide allegedly more protection to the reflectin g surfaceof the marker. The markers which have been provided as a result thereofhave not however, proven to be entirely satisfactory. Basically this isbecause the markers as modified most often are found to be more complexin structure and therefore more costly to manufacture. Also, in manyinstances in order to afford added protection to the reflecting surfaceof the marker, it has been necesssary to reduce the visible area of thereflecting surface which in turn disadvantageously affects the opticalefficiency of the marker.

Another undesirable characteristic possessed almost universally by allprior art types of highway reflecting markers is the susceptibilityexhibited thereby for collecting dirt, sand and road generated dust onthereflecting surface of the marker. This, of course, after a period oftime will significantly reduce the optical efficiency of the marker. Inan attempt to obviate this deficiency, there have been embodied intosome markers some form of self-cleansin g means which is intended to beoperable to periodically wipe off the reflecting surfaces. Even thoughmany of these self-cleansing menas have in operation proven to begenerally effective in accomplishing their intended function, it hasnevertheless been found that to equip a marker with such a selfcleansingmeans normally adds significantly to the cost of manufacture of themarker. Thus, since economic considerations are generally of paramountimportance in determining the extent to which such markers are employed,the net effect of increasing the cost thereof is to discourage increaseusage of highway reflecting markers.

Accordingly, it is an object of the present invention to provide a noveland improved highway retroreflecting marker wherein light rays strikingthe reflecting surface of the marker are redirected within the marker,and then are directed back from the marker in the direction of thesource of the light rays.

It is also an object of the present invention to provide such a highwayretroreflecting marker wherein the redirecting surface bearing portionof the marker depresses upon being engaged by a vehicle andautomatically restores itself to its orginal undepressed condition uponits disengagement therewith by the vehicle.

Another object of the present invention is to provide such a highwayretroreflecting marker wherein at least the redirecting surface bearingportion thereof is formed a wear-resistant material so as to resistabrasion caused by blowing sand and grit, and suffing caused byengagement with the tires of passing vehicles or the blade of a passingsnow plow.

A further object of the present invention is to provide such a highwayretroreflecting marker wherein the redirecting surface bearing portionthereof is sufficiently flexible so that dirt, mud or ice which mayaccumulate thereon will be cracked off, i.e., dislodged therefrom whenthe bearing portion is caused to depress.

A still further object of the present invention is to provide such ahighway retroreflecting marker which is relatively inexpensive tomanufacture, is easy to employ, has a relatively long operating life,while yet being capable of efficiently directing light rays which strikethe marker back in the direction of the source thereof.

Yet another object of the present invention is to provide an effectivemethod of delineating particular portions of a road surface by causinglight rays, produced by a passing vehicles lights, to strike markersdesignating particular road surface portions be reflected within themarkers, and then be directed from the markers back towards the vehicle.

SUMMARY OF THE INVENTION It has now been found that the foregoing andrelated objects can be readily attained by means of a highwayretroreflecting marker comprising a housing which includes asubstantially rigid base, and a resiliently depressible cap projectingupwardly from the base. The cap is preferably formed of a relativelywear-resistant synthetic resin and has a prism which is transparent toenable light rays to pass therethrough. The prism also functions toredirect the light rays within the housing at an angle different fromthe angle at which the light rays strike the prism. A retroreflectingmeans is supported in the housing in such a manner as to enable theretroreflecting means to receive light rays redirected from the prismand to enable these light rays to be retroreflected back to the prism.To employ the highway retroreflecting marker, the latter is positionedsuch that the base thereof is located below road level and the capthereof is located above road level whereby light rays striking theprism are redirected within the housing, and then redirected back to theprism and from the prism directed back in the direction of the strikinglight rays.

In accordance with the preferred embodiment of the invention, thehousing of the highway retroreflecting marker is made in two parts, andmeans are provided for joining the cap in sealingly engaging relationwith the base such that a substantially air-tight seal is formedtherebetween, and whereby under the influence of an external force thecap is free to depress into the base compressing the air therein andupon removal of the external force the cap will be returned by the airto its former undepressed condition. The cap of the housing is formed ina plurality of four or five steps with each step including a prism. Byvirtue of the step construction, each prism is afforded the protectionof a natural protective shoulder. A retroreflecting means is mounted onthe bottom wall of the base to receive light rays which are redirectedwithin the housing by the prism and to retroreflect the light rays backto the prism. For the the most effective operation thereof, theretroreflecting means is positioned so that the light rays will incidentthereon at an angle within of normal. The base is provided with a smallvent means which enables water vapor to be vented therefrom, while atthe same time permitting the housing to remain sufficiently air tightthat the cap upon being depressed is still capable of restoring itselfto its undepressed condition.

Certain objects of the invention may be attained in accordance with themethod wherein portions of a highway are delineated by a retroreflectingmarker having a reflective surface. In accord with this method, a markeris placed in a hole below road level so that the redirecting means ofthe marker projects above road level. The marker is positioned so thatthe redirecting means thereof will be struck by the horizontal lightrays produced by an approaching vehicles lights. Upon striking theredirecting means the horizontal light rays are redirected 90 in anapproximate downward beam onto a retroreflecting means. The beam is thenretroreflected upwardly from the retroreflecting means back to theredirecting means. From the redirecting means the beam is directed backhorizontally towards the approaching vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a highwayretroreflecting marker constructed in accordance with the presentinvention;

FIG. 2 is a side elevational view of the highway retroreflecting markerof FIG. 1 in accordance with the present invention;

FIG. 3 is a side elevational view similar to FIG. 2, of the highwayretroreflecting marker of FIG. 1, but with parts broken away forpurposes of clarity of illustration;

FIG. 4 is a cross-sectional view on an enlarged scale 4 a road surfaceand with parts broken away for purposes of clarity of illustration;

FIG. 11 is a side elevational view of a portion of a prism of a highwayretroreflecting marker in accordance with the present inventionillustrating the angle of reflection of light rays striking the prism;

FIG. 12 is a side elevational view of a portion of a distorted prismillustrating the angle of reflection of light rays striking a distortedprism;

FIG. 13 is a side elevational view of yet another embodiment ofhighwaysretroreflecting marker in accordance with the present invention;and

FIG. 14 is a side elevational view of yet still another embodiment ofhighway retroreflecting marker in accordance with the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring to FIGS.1-4 of the drawings, there is illustrated therein a highwayretroreflecting marker, generally designated by reference numeral 10.The marker 10 includes a cap 12, a base 14, and means 16 for seof aportion of the prism of the highway retroreflecting marker of FIG. 1 inaccordance with the present invention;

FIG. 5 is a cross-sectional view of another embodiment of highwayretroreflecting marker in accordance with the present invention;

FIG. 6 is a side elevational view with parts broken away for purposes ofclarity of illustration of still another embodiment of highwayretroreflecting marker in accordance with the present invention;

FIG. 7 is a cross-sectional view of a further embodiment of highwayretroreflecting marker in accordance with the present invention;

FIG. 8 is a cross-sectional view of a still further embodiment ofhighway retroreflecting marker in accordance with the present invention;

FIG. 9 is a top plan view of an alternate construction of a baseemployable with a highway retroreflecting marker constructed inaccordance with the present invention;

FIG. 10 is a side elevational view of the base of FIG. 9 illustratedpositioned in a hole provided therefor in a curing the cap 12 to thebase 14. The cap 12 is formed from a relatively wear-resistant syntheticresin. In this connection it has been found that a synthetic resinsuitable for this purpose is aliphatic isocyanate type urethane DupontNo. 2699, manufactured by Dupont Company of Delaware, which has beencured with polyol type curing agent 80, part I, 4 butanediol and 20 parttrimethylol propane modified to be as resistant to weathering andultraviolet light as possible.

As shown in FIGS. l-4 the cap 12 is preferably molded so as referencehave a stepped construction. More particularly, the cap 12 is made so asto include a plurality of steps 18. Although the cap 12 is depicted inthe drawings as including four steps 18, it is to be understood that thecap 12 could also include a greater or a lesser number of such stepswithout departing from the essence of the invention. The cap 12 furtherincludes a plurality of prism elements or portions 20. The latter aresuitably mounted on the inner surface of the cap 12 adjacent to thethree uppermost steps 18 as viewed with refereence to FIGS. 3 and 4 ofthe drawings. For this purpose, the cap 12 is molded so as to beprovided with three triangularly shaped portions 22. Each of theportions 22 includes a surface 22a which is inclined at an angle ofapproximately 45 to the planes of the steps 18. The surfaces 22aconstitute the light reflecting surfaces and accordingly must be smoothand shiny to function properly. At least the three triangularly shapedportions 22 of the cap 12 are made so as to be transparent whereby toenable light rays, in a manner to be more fully described subsequently,to pass therethrough and strike the light reflecting surfaces 22a.Finally, the cap 12 also is preferably provided along its open end witha rim 24 capable of co-operating with securing means 16 in a mannerwhich will be described more fully hereinafter.

Turning now to a consideration of the base 14, the latter constitutes acanister having a substantially rigid cylindrically shaped side wall 26closed at one end by a bottom wall 28. Although the base 14 ispreferably made of metal, it is to be understood that other materi als,including synthetic resins, or tempered glass, capable of providing thedesired degreee of rigidity to the side wall 26 could also be employedwithout departing from-the essencce of the invention. A retroreflectingmeans 30 comprising one or more reflecting elements is suitably mountedon the inner surface of bottom wall 28. Retroreflecting means 30 isretained on bottom wall 28 by any suitable securing means 32. Thesecuring means 32 may take the form of an adhesive, retaining membersand fasteners for fastening the members to the bottom wall 28, etc. Ifthe base 14 is formed from resin, the retrorefiecting means 30 may besecured to the bottom wall 28 by being molded thereto, or by beingembedded therein. The retrorefiecting means 30 is located on the bottomwall 28 so as to receive light rays redirected, in a manner yet to bedescribed, from the light reflecting surfaces 22a. In accordance withthe preferred embodiment of highway retrorefiecting marker 10, the base14 is provided with a small vent means 34 suitable provided in the sidewall 26. The vent means 34 functions as a means of enabling water vaporto pass from the interior of the base 14 to the exterior of the markerwithout permitting water to flow into the base 14.

Considering next the method of assembling the marker 10, the cap 12,which as previously described is formed from the resilient material, isslid over the open end of the base 14, the latter being provided with asubstantially rigid side wall 26. For this purpose, the internaldiameter of the open end of cap 12 dimensionally corresponds to theexternal diameter of the base 14. With the cap 12 positioned on the sidewall 26 in frictional engagement therewith, the means 16, which as sownin FIGS. 2 and 3 of the drawings preferably comprises a conventionalsnap ring, is slid over the cap 12 and snapped into place against therim 24 whereby to hold the cap 12 securely positioned on the base 14.The securing force imparted by the snap ring 16 is selected to be suchthat the joint between cap 12 and base 14 is substantially air-tight.

With particular attention directed to FIG. 2, the method of employingthe marker 10 will now be set forth. The marker 10 is first assembled asdescribed in the preceding paragraph. A hole 36 is bored in the roadsurface 38 to receive the marker 10. Accordingly, the circumference ofthe hole 36 is made such that it corresponds to the circumference of therim 24 of cap 12. Preferably the hole 36 is bored clear through the hardsurface, bituminous concrete, or plain concrete of the road surface 38so that water will be free to drain to the rock drainage bed under theroad. The depth of the hole 36 therefore exceeds the depth of the base14. Thus, the hole 36 is commonly filled with sand to a depth whereatwhen the marker 10 is positioned in the hole 36, the bottom step 18 asviewed in FIG. 2 is substantially at road level. The marker 10 is thenplaced in the hole 36, and is oriented therein such that the prismportions 20 of the marker 10 are facing in the direction of approachingvehicles.

With the marker 10 so positioned in hole 36, when a vehicle approacheswith its lights ON, the horizontal light rays produced by the vehicleslights strike as schematically represented in FIG. 3 by the dotted line40 the prism portions 20. Only one dotted line 40 has been depicted inFIG. 3 in the interest of clarity of illustration, but it is to beunderstood that other light rays would be simultaneously striking theother prism portions 20. The prism portions 20 which function similar innature to a 90, 4545 binocular prism, reflect the horizontal light rays,i.e., beam of light 90 to an approximate downward beam whih isschematically depicted in FIG. 3 by dotted line 42. Supported in asubstantially horizontal attitude on the bottom wall 28 of base 14 isthe retrorefiecting means 30 which receives the aforedescribed downwardbeam of light. Upon striking the retrorefiecting means 30, which may becomprised of a plurality of small glass bead type reflectors or may becomprised of a plurality of small cube corner reflectors, the beam oflight made up a plurality of substantially parallel incoming light raysis retroreflected back in the direction of dotted line 42 to the prismportions 20. Upon once again striking the prism portions 20, the beam oflight is redirected and is directed horizontally back towards theapproaching vehicle. The reflecting elements which comprise theretroreflecting means 30 preferably are made as small as practicable sothat the light rays being retroreflected therefrom are as close to theincoming light rays as possible in addition to being parallel to theincoming light rays. Otherwise, some of the light rays beingretroreflected from the retrorefiecting means 30 to the prism portions20 will hit the steps 18 of the cap 12 rather than the prism portions 20thereof and will not be directed towards oncoming traffic. Forconvenience of manufacture, the prism portions 20, if so desired, may besupported in cap 12 at some angle other than that depicted in FIGS. 1-4of the drawings. That is, the prism portions 20 may be so mounted suchthat horizontal light rays which strike the prism portions 20 will notbe redirected vertically but rather at some lesser or greater anglethereto. In which case, the retrorefiecting means 30 should be supportedin the base 14 such that the beam of light being redirected by the prismportion 20 will incident, for purposes of most effective usage of theretrorefiecting means 30, upon the latter at an angle of no more than 10from normal. However, it has been found that the marker 10 is operablefor angles of up to 30. For light to enter a transparent body such asglass or plastic, it can do so most efficiently when the light enters ata path normal to the surface. As the angle of incidence increases, moreand more light is reflected off the surface and what light does enterthe body is refracted at an angle. Accordingly, the markers constructedin accordance with the present invention are all preferably providedwith a stepped vertical surface to receive the light from a motorvehicles headlights. As shown in FIG. 6 however, if so desired, a markerhaving a non-stepped vertical surface may be provided, as will bedescribed more fully hereinafter. The marker of FIG. 6 although stilloperable, will reflect light less efficiently than the marker wherein astepped vertical surface is provided.

Referring again to FIGS. 1-4 of the drawings, the cap 12 of marker 10 asdescribed previously is sealingly engaged to the base 14 such that anair-tight seal is formed therebetween. Thus, when the resilient cap 12is hit by a tire of a passing vehicle or the blade of a passing snowplow, the cap 12 is free to depress into the base 14 compressing the airtherein. When the tire or snow plow blade which hit the cap 12 passesout of engagement therewith, the air in the base 14 which has beencompressed returns the cap 12 to its former undepressed conditionwithout any damage having been incurred by the cap 12. The type ofpolyurethane material from which the cap 12 is preferably formed isspecifically selected to be resistant to abrasion from blowing sand andgrit, and scuffing from ties and scraping of snow plow blades. lnaddition, this material resists hydrolysis at elevated temperatures. Byhaving the surface of the cap 12 made in several steps 18, a naturalprotective shoulder is provided to keep tires and other objects fromcontacting the reflecting surfaces of the cap 12. The practical effectof the step construction in this connection is that it reduces theoverall angle of attack of vehicle tires and snow plow blades strikingthe cap 12. In addition, the stepped construction reduces the amount ofmaterial needed to form the cap 12 while it simultaneously inherentlyprotects the optically smooth prism surfaces thereof. Anothercharacteristic of the cap 12 is that it is substantially flexible sothat any dirt, mud or ice which accumulates thereon will be cracked offthe surface of the cap 12 when the latter depresses.

Because the marker 10 when positioned in the hole 36 is continuouslyexposed to all types of weather conditions which may vary greatly fromday to day particularly with regard to temperatures, it is preferred toprovide the previously described small vent means 34 in the side wall 26of base 14. The vent means 34 is intended to permit water vapor to passfrom the interior of the base 14 while at the same time preventing areverse flow of water into the base 14. To accomplish this function, thevent means 34 preferably includes a diaphragm membrane of the type whichis well know to those skilled in the art and which has commonly beenutilized heretofore for this purpose in other applications. In theabsence of such a vent means 34 temperature differentials existingbetween the inside and outside of the marker 10 could conceivably leadto the establishment of the vacuum'within the base 14. Such a vacuumcould cause the cap 12 to depress into the base 14 and remain sopositioned therein. The vent means 34 functions to minimize thepossibility of such a condition occurring. Of course, the vent means 34must only be made as large as necessary to enable water vapor to escapefrom the inside of the base 14 while at the same time not being so largeas to rupture the air-tightness of the marker 10 whereby the air in thebase 14 would not be compressed when the cap 12 is depressed and thusthe air would be incapable of functioning to return the cap 12 to itsundepressed condition.

For optical purposes, the cap 12, of course, need not be provided with astep construction. The steps 18 are preferably provided primarily formechanical and economical reasons as set forth with more particularityin the preceding paragraphs. As such, other forms of highwayretroreflecting markers embodying configurations which differ from thatof the marker 10 depicted in FIGS. 1-4 of the drawings are alsocontemplated in accordance with the present invention. In thisconnection, reference is made to FIG. of the drawings wherein anotherembodiment of highway retroreflecting marker, designated therein byreference numeral 44, constructed in accordance with the presentinvention is shown. The highway retroreflecting marker 44 insofar asconcerns the structure thereof is very similar to the aforedescribedmarker 10. That is, the marker 44 includes a cap 46, a base 48, andmeans 50 for securing the cap 46 to the base 48. As best seen withreference to FIGS. 5 and 3 of the drawings, the primary differencebetween the marker 44 and the marker resides in the configuration oftheir respective caps, i.e., cap 46 and cap 12, respectively. Morespecifically, whereas the cap 12 of marker 10 is provided with a steppedconstruction, the cap 46 of marker 44 is provided with a top hat-likeconfiguration. The latter is circular in shape, and therefore is capableof reflecting light from any direction. As such, this construction makesthe 8 marker 44 ideally suited for use in airports, parking lots, etc.

Prism portions 52 are mounted within the cap 46 in a manner similar tothat described previously in connection with the description of theretention of prism por tions 20 in cap 12. That is, the prism portions52 are lo cated in the cap 46 such as to lie at an angle to the plane ofthe top surface 46a of cap 46. Furthermore, as in the case of cap 12,the cap 46 is formed so as to be transparent at least in the vicinity ofthe prism portions 52 in order to enable light rays to pass through thecap 46 and strike the prism portions 52. The cap 46 is secured to thebase 48 in the same manner as that described above in connection withthe mounting of cap 12 on base 14. Similarly, the mode of operation ofmarker 44 is the same as marker 10. That is, the marker 44 is adapted tobe positioned in a hole (not shown) suitably provided for this purposeso that the prism portions 52 thereof are oriented in the direction ofap proaching traffic and are visible thereto. With the marker 44 sopositioned, light .rays produced by the lights of an approaching vehiclestrike the prism portions 52 and are redirected downwardly where theyare received by the retroreflecting means 54 mounted on the bottom wall48a of the base 48. These light rays are then retroreflected from theretroreflecting means 54 to the prism portions 52 and directed therefromback into the path of oncoming traffic. The reflection of the light raysfrom the marker 44 thus serves to delineate that portion of the highwaysurface where the marker 44 is located. As in the case of marker 10,should the marker 44 be struck by the tire of a passing vehicle, etc.,the cap 46 will depress into the base 48, compressing the air therein.Once the tire or other object passes from engagement with the cap 46,the air in the base 48 will cause the cap 46 to return to its formerundepressed state.

Referring next to FIG. 6 of the drawings, there is illustrated thereinanother embodiment of a highway retroreflecting marker, generallydesignated by reference numerals 56, constructed in accordance with thepres ent invention, and which like the marker 44 is circular in shape.The marker 56, although structurally it also embodies a cap 58 and abase 60, differs somewhat in construction from either the marker 44 orthe marker 10. The basic difference therebetween resides in the factthat in the marker 56, cap 53 is joined to the base 60 in a mannerdifferent from that which has been heretofore set forth in connectionwith the description of markers 44 and 10. More specifically, in themarker 56 the open end of cap 58 is inserted into the open end of thebase 60 rather than having the base inserted into the open end of thecap as in the case of both marker 44 and marker 10. Preferably,sufficient resiliency exists between the side wall 58a of cap 53 and theside wall 60a of base 60 so that the cap 58 can be inserted into thebase 60 with a snap fit which is sufficiently tight to ensure asubstantially air-tight seal therebe tween. However, if so desired, asuitable adhesive may also, of coursse, be utilized for purposes ofaffixing the cap 58 more securely to the base 60. In addition to theaforedescribed difference, the cap 58 also differs in configuration fromeither the marker 44 or the marker 10. In this connection, the cap 58embodies a generally pyramidically shaped configuration, and has mountedthereon prism portions 62, suitably located such that lightrays strikingthe prism portions 62, as illustrated schematically by dotted line 64 inFIG. 6, are redi- 9 rected therefrom downwardly as shown by dotted line66 to retroreflecting mens (not shown) suitably retained on the bottomwall of base 60 in a manner similar to that previously described abovein connection with the retroreflecting means 54 and 30 of markers 44 and10, respectively. As noted previously, the marker 56 reflects light raysless efficiently than do any of the other markers described previously.This is because the configuration of the cap 58 is such that the lightrays strike the cap 58 at an angle other than normal. Accordingly, someof the light rays are reflected off of the surface of the cap 58 whilethe light rays which enter the body of the latter are refracted at anangle. The mode of operation of the marker 56 is the same as thatdescribed hereinabove with regard to the markers 44 and 10, and as suchit is not deemed to be necessary to include herein a further descriptionof the mode of operation of the marker 56, except to note that the cap58 is also capable of being depressed into the base 60 and of beingreturned to its undepressed state by the air which is compressed in thebase 60 when the cap 58 is depressed therein.

In FIG. 7 of the drawings, there is shown another embodiment of highwayretroreflecting marker, identified therein generally by referencenumeral 68, which is constructed in accordance with the presentinvention. The marker 68 structurally is substantially identical to themarker 56 except insofar as concerns the configuration of the respectivecaps 70 and 58 of the makrers 68 and 56. The manner in which the cap andbase of markers 56 and 68 are joined is more clearly understood withreference to FIG. 7 of the drawings, and the illustration therein of thejoint between the cap 70 and base 72 of the marker 68. The cap 70 ofmarker 68 is formed such as to include a plurality of layer-likeportions 70a, 70b and 700 which have decreasing surface area. Each ofthese layer-like portions 70a, 70b and 700 is suitably provided withprism portions 74. The prism portions 74 function in the same manner asthat described previously for the respective prism portions of each ofthe other embodiments of markers. Thus, horizontal light rays strikingthe prism portions 74 are redirected downwardly onto the retroreflectingmeans 76 positioned on the bottom wall of base 70 and are retroreflectedtherefrom to the prism portions 74 which in turn direct the light raysreceived thereby back into the path of approaching vehicles. Here also,the cap 70 of marker 68 is preferably made from the same type ofsynthetic resins as the cap 12 of marker 10 such that the cap 70 iscapable, when struck, of freely depressing into the base 72 and of beingreturned to its undepressed condition under the influence of the aircompressed in the base 72 when the striking object passes fromengagement with the cap 70.

FIG. 8 depicts a still further embodiment of highway retroreflectingmarker constructed in accordance with the present invention, and whichhas been designated therein generally by reference numeral 78. Themarker 78 includes a cap 80 and a base 82. The cap 80, which is formedpreferably from the same type of transparent synthetic resin as the cap12 of marker 10 has a generally dome-like configuration. The cap 80along its interior is provided with a prism, i.e., reflecting surface84. the marker 78 differs in two major respects from any of the otherembodiments of markers which have been previously described. The firstof these differences resides in the fact that in the marker 78 theretroreflecting means 86 are mounted in the cap 80 rather than on 10 thebottom wall of the base 82 as in the case of the other markers whichhave been previously described. Secondly, the marker 78 is provided witha spring 88 which imparts an upper force against the cap 80, i.e.,biasing the cap 80 to its undepressed condition. Referring again to FIG.8 of the drawings, it can be seen that the spring 88 is positionedwithin the base 82 so as to have one end thereof abutting against theseat 822 provided therefor on the bottom wall of base 82. 'With thespring 88 so positioned therein, the marker 78 is assembled by insertingthe open end of base 82 into the open end of the cap 80. The diameter ofthe cap 80 and base 82 are made such that the fit between the cap 80 andbase 82 is sufficiently tight that the side wall 80a of cap 80 willsecurely encircle the side wall 82b of base 82 and will remaininsealingly engagement therewith notwithstanding the upward force beingapplied to the cap 80 by the spring 88, which in the assembled conditionof the marker 78, has its other end in abutting engagement with a seat80b suitably provided for this purpose in the cap 80. Because of thedifferences in construction, the manner of operation of the marker 78differs in some respects from that described previously for the otherembodiments of markers illustrated in FIGS. 17 of the drawings. Morespecifically the manner of operation of the marker 78 in such that withthe latter suitably-positioned in a hole (not shown) with the cap 80thereof projecting above road level, horizontal light rays coming fromthe light of an approaching vehicle will strike the prism surface 84, asdepicted schematically by the dotted lines 90 in FIG. 8. As discussedabove in connection with the marker 56 of FIG. 6, to the extent that thelight rays striking the cap 80 do so at an angle other than 90, some ofthe light rays will be reflected from the surface of the cap 80 whilethose which do pass into the body of the cap 80 will be refracted at anangle. The latter light rays are then redirected upwardly from the prismsurface 84, as schematically represented in FIG. 8 by the dotted lines92, to the retroreflecting means 86 mounted in the top portion of thecap 80. The light rays striking the retroreflecting means 86 are thenretroreflected back from the retroreflecting means 86 to the prismsurface 84 and are thereafter directed back from the prism surface 84into the .path of approaching vehicles. The reflection of these lightrays back from the prism surface 84 functions to delineate that portionof the highway surface in which the marker 78 is positioned. In theevent that cap 80 is struck by the tire of a passing vehicle, etc., thecap 80 will depress into the base 82 against the bias of spring 88.Thereafter, when the striking object passes from engagment with the cap80, the spring 88 will return the cap 80 to its upper, i.e., normallyundepressed position. Thus, because of the use of the spring 88, it isnot esential that a substantially air-tight seal be provided at thejoint between cap 80 and base 82 since the compression of the air in thebase 82 when the cap 80 depresses therein is not being relied upon forpurposes of returning the cap 80 to its undepressed condition. Further,there is less need to provide suitable vent means (not shown) in theside wall of the base 82. On the other hand, if so desired, the spring88 could be eliminated from the marker 78 and the compression of air inthe base 82 employed to return the cap 80 to its undepressed conditionin the same manner as that set forth hereinabove in connection with thedescription of marker 10. Finally, as shown in FIG. 8, fillets 94 may beformed at suitable locations on the external surface of 1 1 the cap 80as a form of guide means to be engaged by the blade of a passing snowplow should the latter strike the cap 80.

Turning next to a consideration of FIGS. 9 and 10 of the drawings, thereis depicted therein a base 96, embodying an alternate construction,which is capa ble of being employed as one of the components of ahighway retroreflecting marker constructed in accordance with thepresent invention. The base 96 includes a canister portion 98 and astand 100 provided therefor. The portion 98 may be made from anysuitable material such as metal, a synthetic resin, or even of glasswhich has been tempered so that in the event of breakage it will shatterto harmless small pieces. The portion 98 is substantially cylindrical inshape and is provided with a bulge 98a formed along its rim. The bulge98a is intended to coact with the side wall portion of a cap to securethe latter to the base 96 to form a highway retroreflecting marker.Although not shown it is to be understood that suitable retroreflectingmeans capa ble of receiving light rays redirected thereto from the prismportion of a cap would be mounted on the interior of the bottom surfaceof the portion 98. The canister portion 98 is mounted in a stand 100formed of a suitable material such as, for example, aluminum. The stand100 as depicted in FIG. 9 is provided with four outwardly extendingflexible arms 102. Any suitable means may be utilized to mount thecanister portion 98 on the stand 100 such as, for example,,by formingthe portion 98 and the stand 100 as an integral assembly, by providingthe portion 98 with strap-like portions through which the arms 102 maybe inserted, by providing the portion 98 with a plurality of suitablylocated spaced indentations into which projections formed for thispurpose on the stant 100 may be snapped, etc. However, irrespective ofthe manner in which the stand 100 is affixed to the canister portion 98,the important thing is that the arms 102 of stand 100 remain free suchthat when the base 96 is inserted into a hole 104 bored into a suitableroad surface, the arms 102 are capable of flexing inwardly as theyengage the side walls of the hole 104. The arms 102 thus serve as ameans of firmly retaining the base 96 suitably positioned in the hole104. In addition, the stand 100 is also preferably provided with astaking member 106 which projects outwardly from the bottom of stand 100and which is adapted to be driven into the bottom of hole 104 thereby tomore securely retain the base 96 therein.

FIG. 11 illustrates schematically the path taken by horizontal lightrays as they pass through a cap 108 and strike a reflecting surface 110.As viewed therein the horizontal light rays, represented schematicallyby the dotted lines 112, strike the external surface 1082 of the prism,i.e., cap 108 and are all deflected uniformly towards the reflectingsurface 110. Striking the surface 110, the light rays are redirectedapproximately 90 in a downwardly direction, the latter being depictedschematically through the use of the dotted lines 114. As the veticallight rays pass through the bottom surface 108b, they are againuniformly deflected slightly. In the above discussion, it is, of course,assumed that the cap, i.e., prism 108 is made of a transparent material.

FIG. 12 illustrates schematically the path followed by horizontal lightrays when they strike a cap 116 acts as a distorted prism. As depictedtherein, the horizontal light ray, schematically represented by dottedline 118 strikes the external surface 116a and is deflected in aslightly downward direction against the reflecting sur- 12 face 120.Striking the latter surface 120, the light ray represented by dottedline 118 is redirected approximately 90 in a vertical direction, asschematically depicted by means of dotted line 122. On the other hand,the horizontal light ray represented by dotted line 124 in FIG. 12, uponstriking the external surface 116a is deflected thereby slightlyupwardly against the relfecting surface 116a is deflected therebyslightly upwardly against the reflecting surface 120. Upon striking thesurface 120, this substantially horizontal light ray is also redirectedapproximately 90 in a vertical direction as schematically shown by meansof dotted line 126. Thus, with reference to FIGS. 11 and 12 of thedrawings, it can be seen that the optical efficiency of a highwayretroreflecting marker constructed in accordance with the presentinvention and embodying either the cap 108 or th cap 116 does not dependon the accuracy of the external surface of the respective cap, i.e., theaccuracy of the prism shape. For as shown with reference to FIG. 12,when the light rays pass through the distorted external surface 116a ofcap 116 they will return equally and correctly distorted, and as shownin FIG. 11, when the light rays pass through the undistorted externalsurface 108a of cap 108 they will return equally and correctlyundistorted.

Turning now to FIG. 13 of the drawings, there is depicted therein a cap128, which is capable of being supported on a base such as the base 96of FIGS. 9 and 10 of the drawings whereby to provide a highwayretroreflecting marker in accordance with the present invention. Forthis purpose, the cap 128 is provided with a vertically extendingdepending flange 130, which is dimensioned so that a base (not shown)may be inserted therein with a snap fit whereby to secure the cap 128and the base (not shown) together. As illustrated in FIG. 13, one face132 of the cap 128 is configured so as to be substantially straight,i.e., is not provided with a step-like configuration. A plurality ofprism portion 134 are provided adjacent the inner surface of the face132. The nature and function of the prism portions 134 are substantiallythe same as that of the prism portions 22 of cap 12 which have beendescribed previously hereinabove. More particularly, with the cap 128mounted on a suitable base and this assembled unit positioned adjacent aroadway so that the light rays of an oncoming vehicle will strike theface 132 of cap 128, the light rays as schematically represented bydotted line 136 in FIG. 13 pass through the face 132 and are deflectedslightly as they pass therethrough. The light rays strike the prismportions 134 and are redirected in a generally downwardly direction asindicated by means of the dotted line 138, to a retroreflecting means(not shown) suitably mounted within the base (not shown) on which thecap 128 is supported. From the rtroreflecting means the light rays areretroreflected back to the prism portions 134 from where the light raysare directed back towards the oncoming vehicle from whence the lightrays originated.

With the face 132 of the cap 128 configured as shown in FIG. 13, it hasbeen found that when the face 132 is engaged by the tire of a passingvehicle, a rubbing action takes place between the tire and the face 132.The effect of this rubbing action is to clean from the face 132 any drydust and/or oily film which may have accumulated thereon. Thisself-cleaning feature of the cap 128 is a desirable characteristicthereof.

As'was mentioned previously hereinabove, the light rays which strike theface of a highway retroreflecting marker constructed in accordance withthe present invention may be redirected within the housing at some angleother than 90, in which case the retroreflecting means supported withinthe marker 10 is suitably located whereby to be positioned so that thelight rays which are being redirected will incident upon theretroreflecting means. This is most clearly understood with reference tothe illustration of the highway retroreflecting marker 140 depicted inFIG. 14 of the drawings. As shown therein, the marker 140 includes a cap142 and a base 144. Both the cap 142 and the base 144 have asubstantially circular shape. The cap 142 is provided with a verticallyextending depending flange 146, the diameter of which is such that thebase 144 is capable of being inserted therein with a snap fit whereby tosecurely mount the cap 142 on the base 144. Although not shown, it is tobe understood that some other form of securing means could be utilized,if so desired, for purposes of mounting the cap 142 on the base 144. Thecap 142 is provided with a face 148 which is substantially straight,i.e., does not have one or more steps formed therein. A plurality ofprism portions'l50 are provided adjacent the inner surface of the face148. As indicated by the dotted lines 152, 154 and 156,the mode ofoperation of the marker 140 is such that when light rays from anoncoming vehicle strike the face 148, they pass therethrough the strikethe prism portions 150. This causes the light rays to be refracted sothat they are redirected within the marker 140 at an angle ofapproximately 45 from the angle at which the light rays entered themarker 140. However. it is to be understood that these light rays couldalso be refracted at some angle other than 45.

A retroreflecting means 158 is depicted in FIG. 14 of the drawings,supported within the base 144 in a position wherein the redirected lightrays may incident thereupon. The retroreflecting means 158, which mayhave any of the constructions which have been set forth hereinabove inconnection with the description of the other retroreflecting means, isoperable to reflect the light rays which strike it back towards theprism portions 150 and the inner surface of the face 148 from whence thelight rays are redirected back towards the oncoming vehicle. It shouldbe noted that the light rays which strike the retroreflecting means 158are redirected thereagainst as a result of being refracted. During thecourse of the description of at least some of the markers set forthpreviously, reference has been made to the light rays being reflected tothe retroreflectng means. However, the significant fact is not whetherthe light rays are redirected by being reflected from the prism portionsor whether they are redirected by being refracted, but rather that thelight rays be redirected substantially perpendicular to the plane of theretroreflecting means. In this regard, the marker significantly isprovided with retroreflecting means suitably supported therein wherebythe light rays after being redirected either by being reflected orrefracted will incident upon the retroreflecting means at an angle ofnot more than 10 from normal, and then will be retroreflected backtowards the prism portions from whence they are directed back in thedirection of the oncoming vehicle.

Although not shown in the interest of maintaining clarity ofillustration, the retroreflecting means 158 may be supported on a baseof charcoal. Such a charcoal base is effective to absorb at least someof the water vapor which may tend to accumulate within the marker 140.Water vapor will tend to accumulate within the marker when the latter isemployed in applications wherein the inside and the outside of themarker 140 are subjected to different temperatures. As was mentionedearlier, another means of eliminting this water vapor is to provide themarker 140 with suitable vent means (not shown) which is operable topermit water vapor to pass therethrough to the outside of the marker 140while at the same time preventing water from entering the interior ofthe marker 140. Where provided, the dimensions of such vent means are sosmall that it has been found that when the cap of the marker isdepressed by virtue of the wheel of a vehicle passing thereof, air isnot forced out of the marker through the vent means but rather the airis compressed within the marker. This results primarily from the factthat the wheel is in contact with the cap for a relatively brief period,i.e., the wheel passes very rapidly over the cap.

Although a plurality of highway retroreflecting markers constructed inaccordance with the present invention have been described hereinaboveand illustrated in the drawings, it is to be understood that many othermodifications may be made therein without departing from the essence ofthe invention. Thus, for example, the cap could be formed from a varietyof different synthetic resins as long as the cap retained its desireddegree of resiliency and resistance against wear. Similarly, the base ofthe marker may be formed from metal, a synthetic resin, or even temperedglass. In addition, the cap may be configured in a variety of otherdiffering shapes as long as there as prism, i.e., redirecting surfacessupported therein which would be visible, when the marker is positionedin a suitable hole in a road surface, to the lights of approachingvehicles. The cap and base may be joined by any suitable means such asthrough the use of adhesives, a metal wire, a snap ring, etc., as longas the particular securing means employed is capable of providing thedesired degree of tightness between the cap and the base. As describedabove, the retroreflecting means comprises a plurality of small glassbead type reflectors. The latter may be of the exposed glass bead type,the encapsulated glass bead type, or the embedded glass bead type.However, if so desired, the retroreflecting means could also comprise aplurality of small reflecting corner cube prism elements. Althoughpreferably, a highway retroreflecting marker constructed in accordancewith the present invention is provided with a suitable small vent means,it is to be understood that for some applications in which the highwayretroreflecting marker is to be employed such a vent means may beunnecessary.

To utilize the highway retroreflectin g marker for purposes ofdelineating a portion of a highway surface, the marker is positioned ina hole in that portion of the highway surface, so that the redirectingmeans is properly oriented in the direction of oncoming traffic. When avehicle approaches with its lights ON, light rays therefrom will strikethe redirecting means of the marker and be redirected to aretroreflecting means mounted within the marker. The light rays strikingthe retroreflecting means are retroreflected back to the redirectingmeans. The light rays upon striking the redirecting means are directedback substantially horizontal into the path of the oncoming traffic. Thereflection of these light rays back from the redirecting means of themarker, after having been redirected and retroreflected within themarker, operates to delineate that portion of the highway surface inwhich the marker has been emplaced.

Thus, it can be seen that the present invention provides a novel andimproved highway retroreflecting marker wherein light rays striking thereflecting surface of the marker are redirected and retroreflectedwithin the marker, and then are directed back from the marker in thedirection of the source of the light rays. In accord with the presentinvention redirecting surface bearing portion of the highwayretroreflecting marker depresses upon being engaged by an object andautomatically retores itself to its former undepressed condition uponthe disengagement therefrom of the object. The highway retroreflectingmarker of the present invention has at least the directing surfacebearing portion thereof formed from a wear resistant resilient materialso as to resist abrasion caused by blowing sand and grit, and scuffingcaused by engagement with the tires of passing vehicles and scrapingcaused by engagement with the blade of a passing snow plow. Further, theresiliency of the surface bearing portion is such that dirt, mud or icewhich may accumulate thereon will be dislodged therefrom when thebearing portion is caused to depress. Moreover, there has been providedin accordance with the present invention a highway retroreflectingmarker which is relatively inexpensive to manufacture, which is easy toemploy, which has a relatively long operating life, yet still is capableof efficiently reflecting light rays, which strike the marker, back inthe direction of the source thereof. Finally, in accord with the presentinvention there has been provided an effective method of delineatingparticular portions of a road surface by causing light rays, produced bya passinig vehicles lights, to strike markers designating the particularroad surface portions, be redirected and retroreflected within themarkers, and then be directed form the markers towards the approachingvehicles.

Having thus described the invention, I claim:

1. A highway retroreflecting marker comprising; a housing having a baseand a resiliently depressible cap projecting upwardly therefrom, atleast said cap being formed from a relatively wear-resistant syntheticresin, said cap being substantially sealingly engaged with said base,and retroreflecting means supported in said housing, said cap having aredirecting means which is transparent to enable light rays to passtherethrough and which redirects the light rays striking saidredirecting means to an angle of less than 30 to the perpendicular tothe plane of said retroreflecting means, said housing being adapted forpositioning of said base thereof and said cap thereof relative to a roadsurface so that light rays striking said redirecting means areredirected within said housing to said retroreflecting means, then areretroreflected from said retroreflecting means to said redirectingmeans, and thereafter are directed back from said redirecting means inthe direction of the source of the light rays.

2. A highway retroreflecting marker as set forth in claim 1 furthercomprising joining means, and wherein said base and said cap are each ofunitary construction and said joining means joins said base and said captogether so as to form a substantially air-tight seal therebetween.

3. A highway retroreflecting marker as set forth in claim 2 wherein saidcap has a stepped construction formed by a plurality of spaced steps,said redirecting means is mounted in said cap in juxtaposed relation to16 said plurality of spaced steps, said base includes a bottom wall,said retroreflecting means is mounted on said bottom wall, and saidjoining means joins said base and said cap together with said basepartially inserted in said cap.

4. A highway retroreflecting marker as set forth in Claim 3 furthercomprising vent means formed in said side wall of said base to enablewater vapor to be transmitted from the interior to the exterior of saidbase.

5. A highway retroreflecting marker as set forth in claim 2 wherein saidcap has a substantially rectangular configuration, said redirectingmeans is mounted in said cap, said base includes a bottom wall, saidretroreflecting means is mounted on said bottom wall, and said joiningmeans joins said base and said cap together with said base partiallyinserted in said cap.

6. A highway retroreflecting marker as set forth in claim 2 wherein saidcap has a substantially pyramidi cal configuration, said redirectingmeans is mounted in said cap, said base includes a bottom wall, saidretrore- 4 flecting means is mounted on said bottom wall, said joiningmeans joins said base and said cap together with said cap partiallyinserted in said base.

7. A highway retroreflecting marker as set forth in claim 2 wherein saidcap includes a plurality of layerlike portions, said redirecting meansis mounted in said cap in juxtaposed relation to said plurality oflayer-like portions, said base includes a bottom wall, saidretroreflecting means is mounted on said bottom wall, and said joiningmeans joins said base and said cap together with said cap partiallyinserted in said base.

8. A highway retroreflecting marker as set forth in claim 1 wherein saidbase and said cap are each of unitary construction, said cap has a domeconfiguration, said redirecting means is mounted in said cap, said baseincludes a bottom wall, said retroreflecting means is mounted on saidbottom wall, and said base and said cap are joined together with saidbase partially inserted in said cap.

9. A highway retroreflecting marker as set forth in claim 8 furthurcomprising spring means supported in said base for biasing said cap toan undepressed condition.

10. A highway retroreflecting marker as set forth in claim 1 whereinsaid base comprises a canister portion having a substantiallycylindrical configuration consisting of a relatively rigid side wall anda bottom wall, a stand having a plurality of outwardly extendingflexible arms, and means for affixing said canister portion to saidstand.

11. A highway retroreflecting marker as set forth in claim 1 whereinsaid redirecting means comprises prism means operable for reflecting thelight rays to said retroreflecting means.

12. A highway retroreflecting marker as set forth in claim 1 whereinsaid redirecting means comprises prism means operable for refracting thelight rays to said retroreflecting means.

13. A highway retroreflecting marker as set forth in claim 1 whereinsaid cap includes at least one face having a planar configuration, andsaid redirecting means is mounted in said cap in juxtaposed relation tosaid one face of said cap.

14. A highway retroreflecting marker as set forth in cliam 13 whereinsaid retroreflecting means is supported in said housing at an angle tothe major axis of said housing. I

15. A highway retroreflecting marker comprising: a housing including adepressible member, a rigid member and means mounting said depressiblemember to said rigid member to form a substantially air-tight sealtherebetween; said depressible member formed of wear-resistant resilientmaterial, and having redirecting means supported thereon operable toredirect light received thereby; said rigid member including at leastone wall having an opening therein; said opening being located injuxtaposed relation to said depressible member; and retoreflecting meanssupported in said rigid member in a position to receive through saidopening of said rigid member the light directed from said redirectingmeans and for retroreflecting the light back through said opening tosaid redirecting means to cause the light to be directed therefrom backin the direction of the source thereof.

16. A highway retroreflecting marker as set forth in claim wherein saiddepressible member has a stepped construction formed by a plurality ofspaced steps, said redirecting means is supported on said depressiblemember in juxtaposed relation to said plurality of spaced steps, saidrigid member further includes a bottom wall, said retroreflecting meansis supported on said bottom wall, and said depressible member is mountedto said rigid member with said rigid member partially inserted into saiddepressible member.

17. A highway retroreflecting marker as set forth in claim 15 whereinsaid depressible member includes at least one face having a planarconfiguration, said redirecting means is supported on said depressiblemember in juxtaposed relation to said one face, said retroreflectingmeans is supported in said rigid member at an angle to the major axis ofsaid housing, and said depressible member is mounted to said rigidmember with said rigid member partially inserted into said depressiblemember.

1. A highway retroreflecting marker comprising; a housing having a baseand a resiliently depressible cap projecting upwardly therefrom, atleast said cap being formed from a relatively wearresistant syntheticresin, said cap being substantially sealingly engaged with said base,and retroreflecting means supported in said housing, said cap having aredirecting means which is transparent to enable light rays to passtherethrough and which redirects the light rays striking saidredirecting means to an angle of less than 30* to the perpendicular tothe plane of said retroreflecting means, said housing being adapted forpositioning of said base thereof and said cap thereof relative to a roadsurface so that light rays striking said redirecting means areredirected within said housing to said retroreflecting means, then areretroreflected from said retroreflecting means to said redirectingmeans, and thereafter are directed back from said redirecting means inthe direction of the source of the light rays.
 2. A highwayretroreflecting marker as set forth in claim 1 further comprisingjoining means, and wherein said base and said cap are each of unitaryconstruction and said joining means joins said base and said captogether so as to form a substantially air-tight seal therebetween.
 3. Ahighway retroreflecting marker as set forth in claim 2 wherein said caphas a stepped construction formed by a plurality of spaced steps, saidredirecting means is mounted in said cap in juxtaposed relation to saidplurality of spaced steps, said base includes a bottom wall, saidretroreflecting means is mounted on said bottom wall, and said joiningmeans joins said base and said cap together with said basE partiallyinserted in said cap.
 4. A highway retroreflecting marker as set forthin claim 3 further comprising vent means formed in said side wall ofsaid base to enable water vapor to be transmitted from the interior tothe exterior of said base.
 5. A highway retroreflecting marker as setforth in claim 2 wherein said cap has a substantially rectangularconfiguration, said redirecting means is mounted in said cap, said baseincludes a bottom wall, said retroreflecting means is mounted on saidbottom wall, and said joining means joins said base and said captogether with said base partially inserted in said cap.
 6. A highwayretroreflecting marker as set forth in claim 2 wherein said cap has asubstantially pyramidical configuration, said redirecting means ismounted in said cap, said base includes a bottom wall, saidretroreflecting means is mounted on said bottom wall, said joining meansjoins said base and said cap together with said cap partially insertedin said base.
 7. A highway retroreflecting marker as set forth in claim2 wherein said cap includes a plurality of layer-like portions, saidredirecting means is mounted in said cap in juxtaposed relation to saidplurality of layer-like portions, said base includes a bottom wall, saidretroreflecting means is mounted on said bottom wall, and said joiningmeans joins said base and said cap together with said cap partiallyinserted in said base.
 8. A highway retroreflecting marker as set forthin claim 1 wherein said base and said cap are each of unitaryconstruction, said cap has a dome configuration, said redirecting meansis mounted in said cap, said base includes a bottom wall, saidretroreflecting means is mounted on said bottom wall, and said base andsaid cap are joined together with said base partially inserted in saidcap.
 9. A highway retroreflecting marker as set forth in claim 8 furthurcomprising spring means supported in said base for biasing said cap toan undepressed condition.
 10. A highway retroreflecting marker as setforth in claim 1 wherein said base comprises a canister portion having asubstantially cylindrical configuration consisting of a relatively rigidside wall and a bottom wall, a stand having a plurality of outwardlyextending flexible arms, and means for affixing said canister portion tosaid stand.
 11. A highway retroreflecting marker as set forth in claim 1wherein said redirecting means comprises prism means operable forreflecting the light rays to said retroreflecting means.
 12. A highwayretroreflecting marker as set forth in claim 1 wherein said redirectingmeans comprises prism means operable for refracting the light rays tosaid retroreflecting means.
 13. A highway retroreflecting marker as setforth in claim 1 wherein said cap includes at least one face having aplanar configuration, and said redirecting means is mounted in said capin juxtaposed relation to said one face of said cap.
 14. A highwayretroreflecting marker as set forth in cliam 13 wherein saidretroreflecting means is supported in said housing at an angle to themajor axis of said housing.
 15. A highway retroreflecting markercomprising: a housing including a depressible member, a rigid member andmeans mounting said depressible member to said rigid member to form asubstantially air-tight seal therebetween; said depressible memberformed of wear-resistant resilient material, and having redirectingmeans supported thereon operable to redirect light received thereby;said rigid member including at least one wall having an opening therein;said opening being located in juxtaposed relation to said depressiblemember; and retoreflecting means supported in said rigid member in aposition to receive through said opening of said rigid member the lightdirected from said redirecting means and for retroreflecting the lightback through said opening to said redirecting means to cause the lightto be directed therefrom back in the direction of the source thereof.16. A highway retroreflEcting marker as set forth in claim 15 whereinsaid depressible member has a stepped construction formed by a pluralityof spaced steps, said redirecting means is supported on said depressiblemember in juxtaposed relation to said plurality of spaced steps, saidrigid member further includes a bottom wall, said retroreflecting meansis supported on said bottom wall, and said depressible member is mountedto said rigid member with said rigid member partially inserted into saiddepressible member.
 17. A highway retroreflecting marker as set forth inclaim 15 wherein said depressible member includes at least one facehaving a planar configuration, said redirecting means is supported onsaid depressible member in juxtaposed relation to said one face, saidretroreflecting means is supported in said rigid member at an angle tothe major axis of said housing, and said depressible member is mountedto said rigid member with said rigid member partially inserted into saiddepressible member.